Better-orderedmultidict

* overall performance improvements (up to 2x)
* added `DeOrderedMultiDict` (double-ended OrderedMultiDict) which has better performance characteristics for `.popfirst(key)` and `popfirstitem()`
* extended performance tests

Published here: [https://pypi.org/project/better-orderedmultidict/0.2.1/](https://pypi.org/project/better-orderedmultidict/0.2.1/)

* improved performance of `.addall()`
* renamed `.update()` to `.extend()`
* added new `.update()` with different behavior
* extended performance tests

Published here: [https://pypi.org/project/better-orderedmultidict/0.1.0/](https://pypi.org/project/better-orderedmultidict/0.1.0/)